title: Structural and magnetic characterization of self-assembled iron oxide nanoparticle arrays.
abstract: We report about a combined structural and magnetometric characterization of self-assembled magnetic nanoparticle arrays. Monodisperse iron oxide nanoparticles with a diameter of 20 nm were synthesized by thermal decomposition. The nanoparticle suspension was spin-coated on Si substrates to achieve self-organized arrays of particles and subsequently annealed at various conditions. The samples were characterized by x-ray diffraction, and bright and dark field high resolution transmission electron microscopy. The structural analysis is compared to magnetization measurements obtained by superconducting quantum interference device magnetometry. We can identify either multi-phase Fe(x)O/γ-Fe(2)O(3) or multi-phase Fe(x)O/Fe(3)O(4) nanoparticles. The Fe(x)O/γ-Fe(2)O(3) system shows a pronounced exchange bias effect which explains the peculiar magnetization data found for this system.
authors.affiliation: Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany. Maria.BenitezRomero@ruhr-uni-bochum.de
authors.forename: M J
authors.initials: MJ
authors.lastname: Benitez
authors.forename: D
authors.initials: D
authors.lastname: Mishra
authors.forename: P
authors.initials: P
authors.lastname: Szary
authors.forename: G A
authors.initials: GA
authors.lastname: Badini Confalonieri
authors.forename: M
authors.initials: M
authors.lastname: Feyen
authors.forename: A H
authors.initials: AH
authors.lastname: Lu
authors.forename: L
authors.initials: L
authors.lastname: Agudo
authors.forename: G
authors.initials: G
authors.lastname: Eggeler
authors.forename: O
authors.initials: O
authors.lastname: Petracic
authors.forename: H
authors.initials: H
authors.lastname: Zabel
mesh_terms: D004553:Electric Conductivity; D005290:Ferric Compounds / Q000032:analysis* / Q000138:chemical synthesis / Q000737:chemistry; D008280:Magnetics; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000032:analysis* / Q000737:chemistry / Q000648:ultrastructure; D010316:Particle Size; D013535:Suspensions / Q000032:analysis / Q000737:chemistry
chemical_list: D005290:Ferric Compounds; D013535:Suspensions; C000499:ferric oxide